Air door assemblies as described above are typically used on the fronts of vehicles to adjust the flow of cooling air through the air flow opening in the air door frame to meet the cooling requirements of the internal combustion engine and the units surrounding it. The at least one air door of the air door assembly is generally motor driven by means of an actuator, with operation being controlled via an air door control device, which may be part of a vehicle control device. The air door control device can control the operation of the air door assembly, i.e. the adjustment of the at least one air door relative to the air flow opening, on the basis of parameters such as the temperature of the coolant in a coolant circuit and/or the temperature of the oil in an oil circuit of the internal combustion engine, and/or according to other parameters.
The air door assembly is used to decrease the amount of time required by the internal combustion engine to heat up to its rated operating temperature. This enables the emission levels of the internal combustion engine during vehicle operation to be reduced, since the internal combustion engine emits fewer pollutants in its exhaust gas at its rated operating temperature than at other operating temperatures, in particular at cold operating temperatures immediately following a cold start.
Under cold weather conditions, for example during the winter, and in colder regions, for example closer to the poles, at other times of the year as well, the air door assembly can freeze up.
Currently, when immobility or limited mobility of the air door assembly caused by icing is detected, attempts are made to break up the ice by increasing the drive torque or the drive power of the air door actuator and, if necessary, by operating the air door assembly in alternating directions. This is accompanied by a substantial increase in the mechanical load on all the components located between the air door actuator and the at least one driven air door, as well as on the connections between the individual components. As a result, the service life of the air door assembly is unnecessarily reduced. Moreover, a successful breaking up of ice on the air door assembly is often accompanied by considerable noise generation.
From DE 10 2013 214286 B4, it is known to deice a radar sensor located in the bumper of a motor vehicle by using air from a ventilation hose which is provided for ventilating the passenger compartment.
A deicing device for the zonal deicing of glass surfaces on a motor vehicle is known from DE 10 2014 201969 A1. In that case, the glass surfaces are deiced by means of electrical resistance heating elements.